1. Field of the Invention
The invention relates in general to a substrate and a substrate bonding device using the same, and more particularly to a substrate with at least double-layered metal layer and a substrate bonding device using the same.
2. Description of the Related Art
The printed circuit board (PCB) is a supporter of electronic elements and provides the connection of wires between the electronic elements. The base of the PCB can be phenolic sheets, glass fabric sheets or various plastic sheets. For example, the base of the FR-4 substrate is formed by epoxy glass fabric sheets.
The flexible printed circuit (FPC) is light, thin, soft and flexible, and has been widely used in many electronic products such as mobile phones, notebook computers, PDAs, digital cameras and liquid crystal displays (LCDs).
Referring to FIG. 1, a cross-sectional side view of a conventional FPC with a single-layered conductive copper foil is shown. The FPC 10 includes a base 11, a copper foil layer 13, and a covering layer 15. The copper foil layer 13 has a bonding portion 14. The covering layer 15 covers the copper foil layer 13 and exposes the bonding portion 14, so that the FPC 10 is bonded with a rigid circuit board (not illustrated) via the bonding portion 14 by way of bonding process which is commonly used for bonding a conventional flexible substrate and a rigid substrate. However, the bonding area of the bonding portion 14 is restricted by the layout spaces of the electronic elements on the substrate, so that the bonding strength between two substrates is too weak to resist the pulling force during the assembly process. As a consequence, problems such as substrate detachment and poor contact may occur easily.